Agustín Rayo's On the Brink of Paradox is free from MIT Press. Took me all summer, which is praise. I can follow every step of the Banach-Tarski proof and still not believe it. That gap is what the title means. direct.mit.edu/books/oa-mon...
On the Brink of Paradox: Highlights from the Intersection of Philosophy and Mathematics
An introduction to awe-inspiring ideas at the brink of paradox: infinities of different sizes, time travel, probability and measure theory, and computabili
direct.mit.edu